1 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA Stratospheric Observatory for Infrared Astronomy R. D. Gehrz Lead, SOFIA Community Task Force (SCTF) Department of Astronomy, University of Minnesota

2 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Outline SOFIA Science Description of the Observatory and Project Status Schedule Summary

3 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Science

4 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Key Science Topics Related to Origins How stars form in our galaxy and other nearby galaxies Chemistry, Mineralogy, and Biology Solar System studies Targets of Opportunity, for example: –Bright Comets –Eruptive variable stars –Galactic and LMC/SMC classical novae –Supernova in our galaxy or other nearby galaxies –Eclipses and Occultations in the Solar System

5 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA and the Chemical Evolution of the Universe

6 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Above 99% of the water vapor Transmission at 14 km >80% from 1 to 800 µm; emphasis on the obscured IR regions Instrumentation: wide variety, rapidly interchangeable, state-of-the art Mobility: anywhere, anytime Twenty year design lifetime A near-space observatory that comes home after every flight The Advantages of SOFIA

7 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Unique Science Capabilities 8 arcmin diameter FOV allows use of very large detector arrays Image size is diffraction limited beyond 15 µm, making images 3 times sharper than Spitzer Space Telescope Because of large aperture and better detectors, sensitivity for imaging and spectroscopy will be similar to the space observatory ISO Ability to adapt to new technologies Ability to track temporal events

8 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Expectations for Improvements in Detectors Due to increases sensitivity and the number of pixels in large format IR detectors, the speed of measurement has doubled every year for the last 40 years

9 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Astrochemistry Most ground state molecular lines in IR or submillimeter Need high spectral resolution throughout which SOFIA has. As sensitive as CSO, but much larger wavelength range is accessible Light molecules: Molecular hydrogen, HD, water, other hydrides in IR and submillimeter The fullerene, C 60, has 4 IR lines in SOFIA’s bands CSO FTS Spectrum of ORION OMC1 Serabyn and Weisstein 1995 SOFIA is a good observatory for studying chemistry in space

10 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Occultation astronomy with SOFIA Pluto occultation lightcurve observed on the KAO (1988) probes the atmosphere SOFIA can fly anywhere on the Earth, allowing it to position itself under the shadow of an occulting object. Occultation studies with SOFIA will probe the sizes, atmospheres, and possible satellites of newly discovered planet-like objects in the outer Solar system. The unique mobility of SOFIA opens up some hundred events per year for study compared to a handful for fixed observatories. SOFIA will determine the properties of Dwarf Planets in and beyond the Kuiper Belt

11 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Today over 200 extrasolar planets are known, and over 15 transit their primary star: SOFIA will fly above the scintillating component of the atmosphere and will provide the most sensitive freely pointing observatory for extrasolar planetary transits after HST and before JWST. SOFIA has instruments that can observe with high signal-to-noise the small variations in stellar flux due to a planet transit and  Provide good estimates for the mass, size and density of the planet  May reveal the presence of, satellites, and/or planetary rings Artist concept of planetary transit and the lightcurve of HD b measured by HST revealing the transit signature SOFIA will determine the properties of new extrasolar planets by use of transits with HIPO and FLITECAM working together Extrasolar Planet Transits

12 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Antennae Galaxies 8  m (red; 160s, 4’ x 4’) HAWC Beam Sizes Henize 206- LMC high mass star formation 24 mm (80s, 20’ x 20’) HAWC Fields of view (Current 12x32 array at 53, 89, 155, 216  m; Circle is total optical FOV) NASA/JPL-Caltech/Z. Wang NASA/JPL-Caltech/V. Gorjian Clues to the evolution of galaxies: starbursts triggered by collisions and star formation in low-metallicity environments

13 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Atmospheric transmission around the HD line at 40,000 feet Deuterium in the universe is created in the Big Bang. Measuring the amount of cold HD (T<50K) can best be done with the ground state rotational line at 112 microns. A GREAT high resolution spectrometer study is possible given ISO detection HD traces the cold molecular hydrogen (Bergen and Hollenbach). HD has a much lower excitation temperature and a dipole pole moment that almost compensates for the higher abundance of molecular hydrogen. In the future, this technique could be used much like the HI 21cm maps but for cold molecular gas. SOFIA will study deuterium in the galaxy using the ground state HD line at 112 microns. This will allow determination the cold molecular hydrogen abundance. Cold Molecular Hydrogen using HD

14 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Classical Nova Explosions

15 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 R. D. Gehrz, et al. 2005, ApJ, in preparation [PID 124] Spitzer Spectra of Nova V382 Vel IRS Short-High IRS Long-High IRS Short and Long-High Spectra: Abundances and Kinematics H I [Ne II][Ne V][Ne III] [Ne V] [O IV][Ne III]

16 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA’s Instrument Complement As an airborne mission, SOFIA supports a unique, expandable instrument suite SOFIA covers the full IR range with imagers and low, moderate, and high resolution spectrographs 4 instruments at IOC; 9 instruments at FOC SOFIA can take full advantage of improvements in instrument technology Both Facility and PI Instruments

17 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA: Science For the Whole Community

18 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA Performance: Spectral Resolution of the First Generation Science Instruments FORCAST SPITZER IRS IRAC MIPS

19 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007

20 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Frequency (THz) SOFIA Wavelength (µm) SPITZER Infrared Space Observatories Herschel SAFIR Ground-based Observatories JWST ? SOFIA provides temporal continuity and wide spectral coverage, complementing other infrared observatories.

21 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Overview

22 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA Overview 2.5 m (98 inch) telescope in a modified Boeing 747SP aircraft –Optical to millimeter-wavelengths –Emphasis on the obscured IR (  m) Operating altitude –39,000 to 45,000 feet (12 to 14 km) –Above > 99% of obscuring water vapor Joint Program between the US (80%) and Germany (20%) First Light Science 2009 –20 year design lifetime –Science Ops at NASA-Ames and Flight Ops at NASA-Dryden –Deployments to the Southern Hemisphere and elsewhere –> hour flights per year –Built on NASA Lear/Kuiper Airborne Observatory Heritage

23 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007

24 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Primary Mirror M1 M2 M3-1 M3-2 Focal Plane Focal Plane Imager Pressure bulkhead Nasmyth tube Spherical Hydraulic Bearing Nasmyth: Optical Layout

25 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 The Un-Aluminized Primary Mirror Installed

26 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Four First Light Instruments Working/complete HIPO instrument in Waco on SOFIA during Aug 2004 Working/complete FLITECAM instrument at Lick in 2004/5 Working FORCAST instrument at Palomar in 2005 Successful lab demonstration of GREAT in July 2005

27 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Status

28 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA Airborne! 26 April 2007, L-3 Communications, Waco Texas: SOFIA takes to the air for its first test flight after completion of modifications

29 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 The aircraft has flown in April 2007 and is now at NASA Dryden FRC for flight certification tests Early Science is expected to occur in 2009 Two instruments have been selected for Early Science - FORCAST: a US 5-40 μm imager - GREAT: a German heterodyne 60 to 200 μm Spectrometer - Both have been tested in the lab or on a telescope Early Science with SOFIA

30 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Summary -Program making progress! -Aircraft structural modifications complete -Telescope installed, several instruments tested on ground observatories -Completed first flight and ferry flight to NASA Dryden -Full envelope flight testing (closed door) has started. -Several subsystems will be installed spring/summer 08 (Door motor drive, coated primary mirror) -First science in ’09 - SOFIA will be one of the primary facilities for far-IR and sub-millimeter astronomy for many years

31 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Schedule

32 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA Schedule (Major Milestones) First Re-Flight Occurred April ’07 Door Drive Delivered Winter ’07 Open Door Flights at DFRC Fall ’08 First Science ‘09 Next Instrument call ‘10

33 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 US General Observer Opportunities First call for science proposals in ’09 Future calls every 12 months First General Observers 2010 Expect ~ 20 General Observer science flights Shared risk with Instrument PI’s Open Observatory with Facility Instruments

34 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Next Call For New Instruments The next call for instruments will be at first Science ~FY10 There will be additional calls every 3 years There will be one new instrument or upgrade per year Approximate funding for new instruments $8 M/yr

35 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Summary SOFIA has unique spectral and temporal coverage –Unique high-resolution spectroscopy: 28 < l < 150 μm –(l/10 μm) arc-sec image quality, unique for 30 < l < ~60 μm –Unique ability to obtain coverage of transient events –Unique long operating lifetime SOFIA will increase its unique complement of capabilities in the future and will be a test-bed of technologies for future Far-IR missions –State-of-the-art large format IR detector arrays –Polarimeteric imaging and spectroscopy SOFIA is a hands-on Far-IR observatory –Will train future mission scientists and instrumentalists SOFIA is on track for first science in 2009

36 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Appendix

37 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 The Initial SOFIA Instrument Complement HIPO: High-speed Imaging Photometer for Occultation FLITECAM: First Light Infrared Test Experiment CAMera FORCAST: Faint Object InfraRed CAmera for the SOFIA Telescope GREAT: German Receiver for Astronomy at Terahetz Frequencies CASIMIR: CAltech Submillimeter Interstellar Medium Investigations Receiver FIFI-LS: Field Imaging Far-Infrared Line Spectrometer HAWC: High-resolution Airborne Wideband Camera EXES: Echelon-Cross -Echelle Spectrograph SAFIRE: Submillimeter And Far InfraRed Experiment

38 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 SOFIA’s 9 First Generation Instruments * Listed in approximate order of expected in-flight commissioning % Operational (August 2004) § Uses non-commercial detector/receiver technology Science

39 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Science Objectives Major Science Programs for SOFIA: –Origin of stars and planetary systems –Planetary bodies that make up our Solar System –Life-cycle of dust and gas in galaxies –Composition of the molecular universe –Role of star formation and black hole activity in the energetics of luminous galaxies SOFIA has a unique suite of instruments that cover a wide range of wavelengths at a wide range of spectral resolution. SOFIA will be continuously upgraded with new instrumentation and will serve as an important technology development platform for future space missions. SOFIA is a highly visible icon for education and public outreach and will immerse educators in the scientific process.

40 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Learjet-KAO Instrumentalists and their Contributions

41 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Great Observatory Operations Costs for FY 08 ObservatoryOps CostsAnnual Operating Hours Cost per Hour HST$105M4400 (50%)$24K Chandra$77M6400 (75%)$10K Spitzer$81M7680 (90%)$12K SOFIA$80M (est) 960/768 (Total/NASA) $104K CONCLUSIONS SOFIA’s total operating costs are comparable to those of the other Great Observatories SOFIA has fewer operating hours (it’s an airplane) SOFIA’s costs include servicing missions with new focal plane instruments every few years

42 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Courtesy of Gary Melnick

43 R. D. Gehrz Astronomy and Astrophysics Advisory Committee, October 12, 2007 Courtesy of Gary Melnick